 Contraception, also known as birth control

and fertility control, is a method or device used to prevent pregnancy.

 Birth control has been used since ancient

times, but effective and safe methods of birth control only became available in the 20th century. The most effective methods of birth control are sterilization by means of vasectomy in males and tubal ligation in females, intrauterine devices (IUDs), and implantable birth control. This is followed by a number of hormone-based methods including oral pills, patches, vaginal rings and injections. Less effective methods include physical barriers such as condoms, diaphragms and birth control sponges and fertility awareness methods . The least effective methods are spermicides and withdrawal by the male without ejaculation . Sterilization, while highly effective, is not usually reversible; all other methods are reversible, most immediately upon stopping them Safe Sex practices, such as with the use of male or female condoms, can also help prevent sexually transmitted infections. Other methods of birth control do not protect against sexually transmitted diseases. CONTRACEPTION METHODS

 Rhythm Method of Contraception involves

the abstinence from sex during ovulation. For pregnancy to occur, the sperm cell must travel through the cervical canal where a sperm can fuse with the egg or ovum. If sperms are prevented from meeting with an ovum, then pregnancy becomes impossibleMECHANISM OF ACTION One of the commonly practiced methods of contraception is to avoid intercourse near the time of ovulation. The difficulty with this method of contraception is predicting the exact time of ovulation. Yet the interval from ovulation until the next succeeding onset of menstruation is almost always between 13 and 15 days. Therefore, if the menstrual cycle is regular, with an exact periodicity of 28 days, ovulation usualy occurs within 1 day of the 14th day of the cycle. If, in contrast, the periodicity of the cycle is 40 days, ovulation usually occurs within 1 day of the 26th day of the cycle. Finally, if the periodicity of the cycle is 21 days, ovulation usually occurs within 1 day of the seventh day of the cycle. Therefore, it is usually stated that avoidance of intercourse for 4 days before the calculated day of ovulation and 3 days afterward prevents conception. But such a method of contraception can be used only when the periodicity of the menstrual cycle is regular. The failure rate of this method of contraception, resulting in an unintentional pregnancy, may be as high as 20 to 25 percent per year. COITUS INTERRUPTUS

 This method is also known as withdrawal

method. This method is unlike any other methods in that it is male-controlled. It involves withdrawal of the penis from the vagina before the man ejaculates. This method prevents pregnancy by preventing contact between the sperm and the egg